1. Field of the Invention
The present invention is directed to conveyor belts and methods for assembling conveyor belts.
2. Description of Related Art
Conveyor systems are commonly used in various industrial fields for material handling and processing purposes. For instance, conveyor systems are used in food processing systems in which food items are placed on the support surface of a conveyor belt and are processed while being conveyed from one location to another. For instance, the food items may be cooked, baked, frozen, washed, or subject to other processing steps while being conveyed on the conveyor belt. Various different types of conveyor belts have been used in such applications such as wire mesh conveyor belts but various hybrid belts have become especially popular in such food processing systems and other applications where a flat support surface is desirable to provide greater support for the objects being conveyed. Moreover, such conveyor systems are used in a helical accumulator such as that disclosed in U.S. Pat. No. 5,070,999 to Layne et al. which allows storage of large number of items in the conveyor system.
In such hybrid conveyor belts, a plurality of elongated rods are interconnected with one another via plurality of links such as drive links that may be mounted to the end of the elongated rods. The elongated rods and the drive links are typically made of metal to ensure sufficiently strong interconnection between the elongated rods. Moreover, the drive links are typically welded to the ends of the elongated rods to maintain the positioning of the elongated rods as the conveyor belt is driven through the conveyor system.
The hybrid conveyor belts also include a plurality of overlay elements which are mounted to the elongated rods of the conveyor belt, the plurality of overlay elements providing the conveying surface. The overlay elements are generally made of a non-metallic material such as plastic, nylon, or other composite materials. The use of such overlay elements has become popular especially in food processing applications because the conveyance surfaces provided by such overlay elements are easy to clean and can be treated to resist growth of pathogens such as germs, fungus, viruses and bacteria. In such a manner, hybrid conveyor belts can aid in the reduction of food borne ailments by improving sanitation.
The overlay elements of a hybrid conveyor belt are typically mounted to the elongated rods in various ways. One common method is by providing the overlay elements with a clip feature which directly clip on to the elongated rods thereby securing the overlay elements thereon. For instance, U.S. Pat. Nos. 3,416,645 to Jones, No. 3,799,328 to Harvey, and No. 4,582,193 to Larsson disclose various hybrid conveyor belts with overlay elements having a clip with vertical openings that allow vertical insertion of the overlay elements on to the elongated rods. However, the present inventors have found limitations in such prior art hybrid conveyor belts as discussed in further detail below that limits the applications in which such conveyor belts can be used.
In other hybrid conveyor belt configurations, the overlay elements are not provided with any vertical openings, but instead are merely provided with transverse openings that slidably receive an elongated rod. In such hybrid conveyor belts, the drive links must be properly mounted to the ends of the elongated rods to ensure that the overlay element does not slide off the elongated rods. However, because the overlay elements are made of plastic or other composite materials and melt when exposed to very high temperatures, metal drive links cannot be readily used since they cannot be welded, or otherwise mounted to the elongated rods. Consequently, drive links made of plastic or other composite material must also be used.
In this regard, U.S. Pat. No. 5,031,757 to Draebel et al. discloses this type of hybrid conveyor belt in which the overlay elements are slid on to the elongated rods. To mount the drive links to the end of the elongated rods, Draebel et al. discloses that the drive links includes an opening for receiving a locking tab that engages a notch provided on the ends of the elongated rod when the locking tab is inserted into the opening of the drive link. In this manner, the overlay elements are prevented from sliding off the elongated rods and the drive links are mounted to the ends of the elongated rods. However, the present inventors have found that there are disadvantages to such prior art hybrid conveyor belts as described hereinbelow.
More specifically, with respect to the hybrid conveyor belts where the overlay elements are clipped to the elongated rods, the present inventors found that these overlay elements often become detached from the elongated rods. For instance, when such overlay elements are used to convey food items which are sticky and adhere to the conveying surface of the overlay elements, the overlay elements tended to detach from the elongated rods together with the food item when the food item is removed from the conveyor belt. In other applications such as when food items are frozen on the conveyor belt, the food items also tended to adhere to the surface of the conveying surface of the overlay element so that upon its removal, the overlay element also became detached from the elongated rod. Therefore, such hybrid conveyor belts having overlay elements which are mounted to the elongated rods using clips as described in the prior art have been found to be inadequate in many applications where the item to be conveyed adheres to the surface of the overlay element.
Moreover, with respect to hybrid conveyor belts where the overlay elements are slid on to the elongated rods and mounted at the ends, the present inventors have found that in certain applications, the mechanism that mounts the drive link to the end of the elongated rods pose sanitation issues. In particular, the securing mechanism such as the locking tab disclosed in Draebel et al. provide crevices and interfacing joints which are very difficult to clean. Thus, these crevices and joints provide an environment in which bacteria, mold, and fungus can readily grow and viruses can be conveyed and transferred, thus resulting in unsanitary conditions for food processing applications.
Moreover, in the prior art conveyor belts such as that disclosed in Draebel et al., the drive links cannot be readily mounted to the ends of the elongated rods without such locking tabs or similar locking mechanisms. As previously described, the drive links cannot be mounted to the end of the elongated rods using the conventional methods such as welding or other high temperature processes since the overlay element which is slidably received on to the elongated rod is typically made of a non-metallic material such as plastic, nylon, or other composite materials which will melt or otherwise be damaged by application of such high temperatures. Correspondingly, this also requires the use of non-metallic drive links with locking mechanisms with the associated disadvantages noted above since the integral locking mechanisms cannot be economically incorporated into such metal drive links.
Therefore, there exists an unfulfilled need for a conveyor belt with overlay elements in which the overlay elements are not easily removed from the conveyor belt. There also exists an unfulfilled need for such a conveyor belt with mechanisms for resisting removal of the overlay elements. In addition, there also exists an unfulfilled need for such a conveyor belt which will allow high temperature processing at the ends of the elongated rods, even when the overlay elements are made of a non-metallic material. Lastly, there also exists an unfulfilled need for such a conveyor belt in which facilitates cleaning so as to facilitate maintenance of sanitary conditions.
In view of the foregoing, one advantage of the present invention is in providing a conveyor belt with overlay elements in which overlay elements are not easily removed from the conveyor belt unintentionally.
Another advantage of the present invention is in providing such a conveyor belt which will allow high temperature processing in its manufacture, even when the overlay elements are made from a non-metallic material.
Still another advantage of the present invention is in providing such a conveyor belt which will minimize crevices to facilitate maintenance of sanitary conditions on the conveyor belt.
Yet another advantage of the present invention is in providing such a conveyor belt with a retainer to resist removal of the overlay elements.
Furthermore, still another advantage of the present invention is in providing such a conveyor belt with a locking mechanism to resist removal of the overlay elements.
Yet another advantage of the present invention is in providing a method of assembling a conveyor belt that will resist removal of the overlay elements.
In accordance with one embodiment of the present invention, conveyor belt is provided including a plurality of elongated rods interconnected with each other, a plurality of slide-in overlay elements, each having an upper surface and a transverse opening sized to slidably receive one of the elongated rods, and a plurality of retaining overlay elements, each having a transverse opening sized to receive one of the elongated rods and a vertical opening to allow vertical insertion of each retaining overlay element on to an elongated rod in a manner that each retaining element is adjacent to a slide-in overlay element.
In accordance with one preferred embodiment of the present invention, the vertical opening of each retaining overlay element includes a retainer that resists removal of the retaining overlay element from the elongated rod. In this regard, the retainer includes a clip portion that sizes the vertical opening smaller than a thickness dimension of the elongated rod in one embodiment. In addition, the combined transverse length of the slide-in overlay elements is longer than the combined transverse length of the retaining overlay elements in another embodiment.
In accordance with another preferred embodiment of the present invention, the slide-in overlay element includes a lock mechanism which locks an end of the retaining overlay element with an end of the slide-in overlay element to resist removal of the retaining overlay element. In this regard, in one embodiment, the lock mechanism includes a lock protrusion provided on an end of the slide-in overlay element that abuts the retaining overlay element, the lock protrusion being positioned proximate to the upper surface of the slide-in overlay element. The lock mechanism further includes an interlock protrusion provided on an end of the retaining overlay element that abuts the slide-in overlay element, the interlock protrusion being offset relative to the lock protrusion of the slide-in overlay element, thereby allowing interlocking of the lock protrusion with the interlock protrusion. In one such embodiment, the lock protrusion is positioned flush with the upper surface of the slide-in overlay element.
In accordance with still another embodiment of the present invention, each of the plurality of slide-in overlay elements and the plurality of retaining overlay elements include a plurality of spaced intermeshing extensions that form receiving compartments adapted receive intermeshing extensions of an adjacent overlay element thereby interlinking adjacent overlay elements together. In this regard, the transverse opening of each of the plurality of slide-in overlay elements and the plurality of retaining overlay elements are slots to allow the interlinked overlay elements to be nested together and extended away from one another. Furthermore, in one embodiment, each of the intermeshing extensions include a bulbous tip that are dimensioned so that vertical edge surfaces of the bulbous tip contacts vertical edge surfaces of bulbous tips of adjacent intermeshing extensions when the overlay elements are extended away from one another.
In accordance with yet another embodiment of the present invention, the retaining overlay element are preferably formed from a non-metallic material and the conveyor belt includes at least one link mounted to an end of the elongated rod using a high temperature process such as by welding and/or button head forming. The link preferably includes a transverse opening sized to receive an elongated rod therein and is formed from a non-metallic material. In one embodiment, the link is preferably a drive link adapted to facilitate driving of the conveyor belt. In another embodiment, the link includes an extension portion extending beyond the end of the elongated rod. In this regard, the extension portion is adapted to guide conveyance path of the conveyor belt in one embodiment while in another embodiment, the extension portion includes a drive surface adapted frictionally contact a drive mechanism to thereby drive the conveyor belt.
In accordance with another aspect of the present invention, a method of assembling a conveyor belt is provided including the steps of providing an elongated rod, providing a slide-in overlay element with a transverse opening sized to receive the elongated rod, sliding the slide-in overlay element on to the elongated rod, the transverse opening of the slide-in overlay element receiving the elongated rod, providing a retaining overlay element with a vertical opening and a transverse opening sized to receive the elongated rod, and vertically inserting the retaining overlay element on to the elongated rod via the vertical opening.
In accordance with one embodiment, the present method further includes the step of securing the retaining overlay element by clipping the retaining overlay element on to the elongated rod. In another embodiment, the present method includes the step of interlocking abutting ends of the retaining overlay element and the slide-in overlay element to resist removal of the retaining overlay element. Preferably, at least one of the slide-in overlay element and the retaining overlay element is formed from a non-metallic material and further includes the step of moving the slide-in overlay element away from an end of the elongated rod and subjecting the end of the elongated rod to a high temperature process before inserting the retaining overlay element on to the elongated rod. The high temperature process may include at least one of welding and button head forming.
In accordance with yet another embodiment, the present invention further includes the step of sliding a link with a transverse opening on to an end of the elongated rod, and sliding the link away from the end of the elongated rod before subjecting the end of the elongated rod to the high temperature process. The link mounted to the end of the elongated rod may be a drive link and/or include an extension portion extending beyond the end of the elongated rod.
These and other advantages and features of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention when viewed in conjunction with the accompanying drawings.